- The long-term goal of the proposal is to understand the molecular regulatory mechanisms that maintain the cellular proliferative capacity and the signals that trigger the cells to cease proliferation. The principal investigator believes that understanding transcriptional regulation during the transition from proliferation to differentiation is an important step toward elucidation of these regulatory processes. The principal investigator has recently discovered a novel zinc finger protein, basonuclin. Basonuclin is present in the nuclei of keratinocytes in the proliferative compartment of epidermis and the germ cells in the seminiferous tubules of testis. The principal investigator hypothesizes that basonuclin is a transcription factor participating in the regulation of cellular proliferative potential (capability). Specific Aim 1 is to demonstrate that basonuclin is a DNA binding protein with sequence specificity. The approach is to select these targets from a pool of random sequences by electrophoresis mobility shift assay (EMSA) using zinc finger peptides. Specific Aim 2 will identify the genes whose promoters contain the basonuclin target sequence. The principal investigator aims to identify the genes that are controlled by basonuclin and thereby to understand the regulatory network in which basonuclin is a part. The principal investigator will search the DNA data base for promoters that contain the target sequence of basonuclin and to analyze the genomic fragments that are selected for their ability to bind to the bacterial produced full length basonuclin. Specific Aim 3 will map basonuclin's binding sites on mitotic chromosomes. The association of basonuclin with mitotic chromatin is highly unusual. The principal investigator aims to identify the mitotic chromosomes that contain basonuclin and to clone these binding sites, which may or may not be the same binding sites present on the bare DNA (lacking histones) that is studied in Aim 2. The virtue of molecules such as basonuclin in the study of biochemical and genetic regulation of cellular events is that it is a regulator that is also regulated. By studying it, the principal investigator expects to gain knowledge not only about basonuclin, but also about the regulatory hierarchy in which it is a part. The principal investigator believes that the proposed study of the biological function of basonuclin will enhance the knowledge about the molecular regulation of cellular proliferative potential. This knowledge is needed, he believes, to devise better medical treatment for proliferation-related abnormalities in the skin, such as cancer, psoriasis, and impaired wound healing. It is also essential for designing better culture conditions to produce large quantities of normal human cells for grafting and engineering purposes.